Here's a link to the proper section of the TSRM...
http://www.cygnusx1.net/Supra/Librar....aspx?S=FA&P=9
And as soon as you can you really need to have that broken Tstat bolt drilled out or otherwise removed and replaced. Atlanta traffic and all it implies is no place for a Supra with a compromised cooling system, and with that bolt being broken off you're practically begging for trouble if you drive it in that condition.